[Grades] Add a notification badge when a new grade is released

**Is your feature request related to a problem? Please describe.**
Would be really neat to have a small badge above the grade button that has a new grade in it. For example, something like this could be use above grade button that has some new content:


It would encourage the user to go see their grades faster and also simplify the application use when they want to go see their grades for a specific class.

**Describe the solution you'd like**
The solution should contained the following:

- When loading the page load all cache seen info and show the badge above the appropriate course.
- Provide a way to save a course in the cache where a modification was seen (we can use the hashcode of the evaluation to know if it was saved or not)
- When a course grade_details is open, save the course in the cache.
- [Optional] (but cool :wink: ) show also the specific evaluation with a notif badge and save it in cache as seen only when scrolling to it.
- Tests :test_tube:

**Describe alternatives you've considered**
N/A
but if there is discussion to have I'm always open for ideas :smile:

**Additional context**
https://pub.dev/packages/badges